dgb-wallet/packages/mobile

@dgb-wallet/mobile

DigiByte.X Wallet — React Native (Expo) app. Ports the same recovery-first UI as @dgb-wallet/web-ui using React Native primitives (View/Text/Pressable instead of div/button).

Shares the same crypto core via the monorepo workspace — no re-implementation of address derivation or PSBT signing.

Prerequisites

• Node 20+ (already installed)
• Android Studio with:
  • Android SDK (API 34+ recommended)
  • An Android emulator device (e.g., Pixel 6 running Android 14)
  • ANDROID_HOME env var set (usually %LOCALAPPDATA%\Android\Sdk)
• Java JDK 17 (Android Studio bundles one)

First run

cd "D:\Dev\SilentCode\Digibyte"

# 1. Install (installs Expo + RN + polyfills in packages/mobile)
npm install

# 2. Start Android emulator from Android Studio (Device Manager > play)

# 3. Boot the app
npm run android -w @dgb-wallet/mobile

First launch takes ~5 min: Metro bundles ~2000 modules, Expo compiles the dev client, APK installs on emulator. Subsequent launches are seconds.

What's in the box (v0.0.2)

• Three tabs, bottom navigation via @react-navigation/bottom-tabs:
  • Import — paste seed, live BIP39 validation, derive all 5 descriptor paths, show first 5 addresses per path.
  • Balance — derive BIP84 xpub, POST to the wallet daemon at http://10.0.2.2:5174/balance (Android emulator alias for host localhost), show totalSats + UTXO list + filter/block/timing stats.
  • Send — build & sign a BIP84 P2WPKH tx, broadcast via daemon; toggle between Dandelion++ (default) and direct fan-out.

Balance and Send both talk to @dgb-wallet/p2p's daemon over HTTP — run it in a separate terminal before opening those tabs:

npm run daemon -w @dgb-wallet/p2p

For an iOS simulator, edit src/rpc-native.ts and switch DAEMON_URL to http://127.0.0.1:5174 — the 10.0.2.2 alias is Android-emulator-only.

Verified state

• tsc --noEmit passes cleanly on packages/mobile (once npm install has run at the repo root — the @react-navigation/*, react-native-screens, and react-native-safe-area-context deps hoist into packages/mobile/node_modules).
• The daemon HTTP contract that src/rpc-native.ts calls (POST /balance with {xpub, purpose, account, gapLimit}, POST /broadcast with {hex}) is verified end-to-end via the @dgb-wallet/web-ui package, which hits the same daemon endpoints with the same crypto core. The mobile screens are a straight React Native port of those flows.
• Emulator boot is blocked on Intel VT-x being disabled in BIOS on the current dev machine — see next section.

Requires: hardware virtualization

Android x86 emulators need a hypervisor. On Windows that means either AEHD (Android Emulator Hypervisor Driver, HAXM's successor) or WHPX (Windows Hypervisor Platform). Both silently fall over if Intel VT-x / AMD-V is off in firmware.

Check first:

Get-CimInstance Win32_Processor | Select-Object Name, VirtualizationFirmwareEnabled, SecondLevelAddressTranslationExtensions

If VirtualizationFirmwareEnabled is False, no software fix will work — reboot into BIOS/UEFI, find "Intel Virtualization Technology" / "VT-x" (typically under Advanced → CPU Configuration or Security), enable it, save, boot back to Windows.

Then install AEHD (already downloaded with the SDK):

cd "$env:LOCALAPPDATA\Android\Sdk\extras\google\Android_Emulator_Hypervisor_Driver"
.\silent_install.bat        # runs elevated via UAC
sc query aehd               # STATE should say RUNNING

If AEHD's service is already registered but stops with sc start aehd returning error 4294967201 (ERROR_NOT_SUPPORTED), that's the VT-x-off symptom — driver installed fine, but the CPU refuses to enter root mode. Fix in BIOS.

Then boot the emulator normally:

& "$env:LOCALAPPDATA\Android\Sdk\emulator\emulator.exe" -avd Pixel_3a_API_30_x86

Crypto polyfills — the non-obvious bit

React Native has no crypto or Buffer globals like Node/browser. This app plugs those gaps via:

• react-native-quick-crypto — implements Node's crypto API using native code (fast, correct)
• buffer npm package — Buffer polyfill
• react-native-get-random-values — polyfills crypto.getRandomValues used by bip39.generateMnemonic

All wired up in index.js (loads BEFORE any app code) and metro.config.js (aliases so bitcoinjs-lib et al find them).

Layout

packages/mobile/
├── app.json                  Expo config (name, package, orientation)
├── babel.config.js           babel-preset-expo
├── index.js                  Entry — installs crypto polyfill THEN app
├── metro.config.js           Monorepo + Node-shim resolution
├── src/
│   ├── App.tsx               Root (header + bottom-tab navigation)
│   ├── ImportScreen.tsx      Recovery UX in RN primitives
│   ├── BalanceScreen.tsx     P2P daemon /balance client
│   ├── SendScreen.tsx        P2P build+sign+broadcast (Dandelion default)
│   ├── derive.ts             Same as web-ui/src/derive.ts (kept parallel for now)
│   ├── rpc-native.ts         Fetch helpers pointed at 10.0.2.2:5174
│   └── styles.ts             Shared StyleSheet across screens
└── tsconfig.json             extends expo's base config

Known limitations at this scaffold stage

• No on-device run yet. Balance/Send tabs are wired against the daemon HTTP contract that the browser web-ui exercises today, but they haven't run on an actual Android surface — that's blocked by VT-x on this workstation (see previous section). A physical Android phone with USB debugging would unblock the same verification without touching BIOS.
• No secure keystore integration yet — imported seeds live in component state only. Production will use expo-secure-store (Android Keystore / iOS Keychain).
• Send tab uses BIP84 only, single account, flat 5000-sat fee (same demo scope as web-ui).